非均质边坡强度折减法折减范围研究

Scope of strength reduction for inhomogeneous slopes

目前强度折减法分析边坡稳定的研究多针对均质简单边坡,而当涉及到非均质边坡时,就存在选择局部区域还是选择所有区域进行强度折减的问题。以FLAC3D为平台,基于计算收敛性准则利用内嵌FISH语言二次开发了能够自动搜索安全系数的整体强度折减代码和局部强度折减代码;结合特征点位移突变准则利用内嵌FISH语言二次开发了依据位移–折减系数曲线判定边坡安全系数的整体强度折减代码和局部强度折减代码;通过有关算例,验证了自编程序的有效性。在此基础上,针对一个非均质边坡分别按照整体强度折减与局部强度折减进行稳定性数值分析,研究表明,两者所得安全系数并不总是一致,整体强度折减法计算所得安全系数与极限平衡法计算结果较为一致,而局部强度折减法若不能合理选择折减区域则不能正确评价边坡的稳定性。因此,采用强度折减法对非均质边坡进行稳定性分析时,建议对整个模型都进行折减。

At present,the researches on the stability of slopes by strength reduction technique mainly refer to homogeneous slopes.However,for the inhomogeneous slopes,some problems should be taken into consideration,such as the scope of strength reduction,global or local region？ Therefore,on one hand,the program code of global/local strength reduction method is compiled based on the criterion of the iteration non-convergence by FISH language embedded in the FLAC3D,which can automatically search the safety factor.On the other hand,the program code of global/local strength reduction method is compiled based on the criterion of uncontrolled displacement at a certain characteristic node on the slope surface,which can draw the curve of displacement-reduction factor used for the estimation of the safety factor.Furthermore,its validity is demonstrated through comparative studies for a typical example.Finally,an inhomogeneous slope is analyzed based on the proposed program.The results show that the safety factors of the inhomogeneous slope solved by these two methods are not always equal and that the safety factor computed by the global strength reduction method is more reasonable and precise.It is advised that the global strength method should be better than the local strength method when the inhomogeneous slope is analyzed.